.\" -*- nroff -*-
.\" Copyright 2010 Cisco Systems, Inc.  All rights reserved.
.\" Copyright 2006-2008 Sun Microsystems, Inc.
.\" Copyright (c) 1996 Thinking Machines Corporation
.\" Copyright (c) 2020      Google, LLC. All rights reserved.
.\" $COPYRIGHT$
.TH MPI_Group_compare 3 "#OMPI_DATE#" "#PACKAGE_VERSION#" "#PACKAGE_NAME#"
.SH NAME
\fBMPI_Group_compare \fP \- Compares two groups.

.SH SYNTAX
.SH C Syntax
.nf
#include <mpi.h>
int MPI_Group_compare(MPI_Group \fIgroup1\fP, MPI_Group\fI group2\fP,
	int\fI *result\fP)

.fi
.SH Fortran Syntax
.nf
USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_GROUP_COMPARE(\fIGROUP1, GROUP2, RESULT, IERROR\fP)
	INTEGER	\fIGROUP1, GROUP2, RESULT, IERROR\fP

.fi
.SH Fortran 2008 Syntax
.nf
USE mpi_f08
MPI_Group_compare(\fIgroup1\fP, \fIgroup2\fP, \fIresult\fP, \fIierror\fP)
	TYPE(MPI_Group), INTENT(IN) :: \fIgroup1\fP, \fIgroup2\fP
	INTEGER, INTENT(OUT) :: \fIresult\fP
	INTEGER, OPTIONAL, INTENT(OUT) :: \fIierror\fP

.fi
.SH INPUT PARAMETERS
.ft R
.TP 1i
group1
First group (handle).
.TP 1i
group2
Second group (handle).

.SH OUTPUT PARAMETERS
.ft R
.TP 1i
result
Integer which is MPI_IDENT if the order and members of the two groups are the same, MPI_SIMILAR if only the members are the same, and MPI_UNEQUAL otherwise.
.ft R
.TP 1i
IERROR
Fortran only: Error status (integer).

.SH DESCRIPTION
.ft R
MPI_IDENT results if the group members and group order is exactly the same in both groups. This happens for instance if group1 and group2 are the same handle. MPI_SIMILAR results if the group members are the same but the order is different. MPI_UNEQUAL results otherwise.

.SH ERRORS
Almost all MPI routines return an error value; C routines as the value of the function and Fortran routines in the last argument.
.sp
Before the error value is returned, the current MPI error handler is
called. By default, this error handler aborts the MPI job, except for I/O function errors. The error handler may be changed with MPI_Comm_set_errhandler; the predefined error handler MPI_ERRORS_RETURN may be used to cause error values to be returned. Note that MPI does not guarantee that an MPI program can continue past an error.

